Ticket #1434: patch1434

Index: lib/symfony/helper/DateHelper.php
===================================================================
--- lib/symfony/helper/DateHelper.php   (Revision 3422)
+++ lib/symfony/helper/DateHelper.php   (Arbeitskopie)
@@ -36,7 +36,12 @@
 function format_date($date, $format = 'd', $culture = null, $charset = null)
 {
   static $dateFormats = array();
-
+  
+  if (is_null($date)) 
+  {
+   return null;
+  }
+  
   if (!$culture)
   {
     $culture = sfContext::getInstance()->getUser()->getCulture();
Index: lib/symfony/helper/NumberHelper.php
===================================================================
--- lib/symfony/helper/NumberHelper.php (Revision 3422)
+++ lib/symfony/helper/NumberHelper.php (Arbeitskopie)
@@ -19,6 +19,11 @@
 
 function format_number($number, $culture = null)
 {
+  if (is_null($number)) 
+  {
+   return null;
+  }
+   
   $numberFormat = new sfNumberFormat(_current_language($culture));
 
   return $numberFormat->format($number);
@@ -26,6 +31,11 @@
 
 function format_currency($amount, $currency = null, $culture = null)
 {
+  if (is_null($amount)) 
+  {
+   return null;
+  }
+   
   $numberFormat = new sfNumberFormat(_current_language($culture));
 
   return $numberFormat->format($amount, 'c', $currency);